Ambulatory infusion pumps and reservoir assemblies for use with same

ABSTRACT

Ambulatory infusion pumps, medicament reservoirs, and plungers, including both dynamic and static seals, plus related components, as well as component combinations and related methods.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/042,093, filed Feb. 11, 2016, which claims the benefit of andpriority to U.S. Provisional Application Ser. No. 62/117,565, filed Feb.18, 2015 and entitled “Ambulatory Infusion Pump Seals,” which areincorporated herein by reference in their entirety.

BACKGROUND 1. Field

The present devices and methods relate generally to ambulatory infusionpumps and seals for those pumps.

2. Description of the Related Art

Ambulatory infusion pumps (also referred to herein simply as “infusionpumps”) are relatively small, at least substantially self-containeddevices that are used to introduce drugs and other infusible substances(collectively “medicament”) into patients' bodies. Some infusion pumpsare configured to be worn on a belt, carried in a clothing pocket, orthe like. Other infusion pumps are configured to be adhered to skin inpatch-like fashion. Infusion pumps are advantageous in that they may beused to, for example, subcutaneously introduce (or “infuse”) medicamenton an ongoing or even continuous basis outside of a clinicalenvironment. Infusion pumps are also advantageous in that they greatlyreduce the frequency of subcutaneous access events such as needle-basedshots. One example of a medicament that may be introduced by an infusionpump is a liquid formulation of insulin. Other exemplary medicamentsthat may be introduced by an infusion pump include, but are not limitedto, drugs that treat cancers and drugs that suppress the perception ofpain.

Many conventional infusion pumps have improved patient health andquality of life. Nevertheless, the present inventors have determinedthat conventional infusion pumps are susceptible to a wide range ofimprovements. By way of example, but not limitation, the presentinventors have determined that it would be desirable to provide aninfusion pump that is smaller, simpler, and less costly thanconventional infusion pumps, while also being more accurate thanconventional infusion pumps.

SUMMARY

An infusion pump reservoir assembly in accordance with at least one ofthe present inventions includes a medicament reservoir and a plungerthat is moveable within the medicament reservoir and includes a dynamicseal. The assembly may further include a static seal. When the systembegins to dispense medicament, the plunger may automatically disengagefrom the static seal while the dynamic seal remains in contact with theinner surface of the reservoir. The present inventions also includeinfusion pumps including such medicament reservoir assemblies.

A method in accordance with at least one of the present inventionsincludes the step of automatically disengaging a plunger from a staticseal upon commencement of medicament dispensing from an infusion pump.

A method in accordance with at least one of the present inventionsincludes the step of reducing the energy required to begin medicamentdispensing from an infusion pump that includes a plunger by providing astatic seal that automatically disengages from the plunger uponcommencement of medicament dispensing.

The features and attendant advantages of the present inventions willbecome apparent as the inventions become better understood by referenceto the following detailed description when considered in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed description of exemplary embodiments will be made withreference to the accompanying drawings.

FIG. 1A is a perspective view of an exemplary infusion pump system in anassembled state.

FIG. 1B is an exploded perspective view of the infusion pump systemillustrated in FIG. 1A, including a durable assembly and a disposableassembly.

FIG. 2 is a top view of certain components of the infusion pump systemillustrated in FIGS. 1A and 1B.

FIGS. 2A is a schematic view showing a use of the infusion pump systemillustrated in FIGS. 1A and 1B.

FIG. 2B is a schematic view showing another use of the infusion pumpsystem illustrated in FIGS. 1A and 1B.

FIG. 3A is a perspective view of an exemplary durable assembly.

FIG. 3B is a perspective view of certain components of the durableassembly illustrated in FIG. 3A.

FIG. 4A is a perspective view of an exemplary disposable assembly.

FIG. 4B is a perspective view of certain components of the disposableassembly illustrated in FIG. 4A.

FIG. 5A is a perspective view of certain components of a durableassembly and a disposable assembly of an exemplary infusion pump system.

FIG. 5B is a perspective view of the components of the exemplary durableassembly illustrated in FIG. 5A.

FIG. 5C is a perspective view of the components of the exemplarydisposable assembly illustrated in FIG. 5A.

FIG. 6 is a perspective section view of components of the exemplaryinfusion pump system of FIG. 5A, revealing a gap between certaincomponents of the durable and disposable assemblies.

FIG. 7 is a front view showing a patient's skin being cleaned.

FIG. 8 is a flow chart illustrating an exemplary disposable assemblyremoval and replacement method.

FIG. 9 is a perspective view of an exemplary infusion pump system in anassembled state.

FIG. 10 is a perspective view of an exemplary reservoir assembly withthe plunger in the full position.

FIG. 11 is a perspective view of certain components of the reservoirassembly illustrated in FIG. 10.

FIG. 12 is a perspective view of certain components of the reservoirassembly illustrated in FIG. 10.

FIG. 13 is a section view of the reservoir assembly illustrated in FIG.10.

FIG. 14 is a section view of the reservoir assembly illustrated in FIG.10 with the plunger not in the full position.

FIG. 15 is a section perspective view of the reservoir assemblyillustrated in FIG. 10 with the plunger not in the full position.

FIG. 16 is a perspective view of an exemplary reservoir assembly withthe plunger in the full position.

FIG. 17 is a perspective view of certain components of the reservoirassembly illustrated in FIG. 16.

FIG. 18 is a perspective view of certain components of the reservoirassembly illustrated in FIG. 16.

FIG. 19 is a section view of the reservoir assembly illustrated in FIG.16 with the plunger not in the full position.

FIG. 20 is a section view of an exemplary reservoir assembly with theplunger in the full position.

FIG. 21 is an enlarged view of a portion of a FIG. 20.

FIG. 22 is a section view of the reservoir assembly illustrated in FIG.20 with the plunger not in the full position.

FIG. 23 is an enlarged view of a portion of FIG. 22.

DETAILED DESCRIPTION

The following is a detailed description of the best presently knownmodes of carrying out the inventions. This description is not to betaken in a limiting sense, but is made merely for the purpose ofillustrating the general principles of the inventions.

It should also be noted here that the specification describes structuresand methods that are especially well-suited for the subcutaneousdelivery of very high concentration insulin (i.e., U-200 insulin andabove) such as U-500 insulin as well as lower concentration insulin suchas U-100 insulin. Nevertheless, it should be appreciated that thepresent inventions are applicable to a wide variety of infusion pumpsand medicaments. By way of example, but not limitation, the inventionsmay employ, for fluid displacement, a reservoir with a plunger, a fluiddisplacement device in the form of a plunger pusher, and a drivemechanism that includes a motor, or other fluid displacement devices,regardless of the type of reservoir employed, piston pumps (e.g.,electromagnet pumps), MEMS pumps, peristaltic pumps and any othersuitable pumps as well as corresponding drive mechanisms. Exemplaryinfusion pumps that include a reservoir with a plunger, a fluiddisplacement device in the form of a plunger pusher, and a drivemechanism are described in U.S. patent application Ser. No. 12/890,207,filed Sep. 24, 2010, and corresponding U.S. patent publication No.2012/0078170, both of which are incorporated by reference in theirentireties, and in U.S. provisional patent application Ser. No.62/057,273, filed Sep. 30, 2014, and corresponding U.S. patentapplication Ser. No. 14/869,906, filed Sep. 29, 2015, which are alsoincorporated by reference in their entireties. The present inventionsare also applicable to medicaments such as, for example, drugs to maskpain, chemotherapy and other cancer related drugs, antibiotics,hormones, GLP-1, Glucagon, various other drugs that include largemolecules and proteins that may require a high level of deliveryaccuracy, as well as to relatively high concentration insulin (i.e.,U-200 insulin and above) such as U-500 insulin and lower concentrationinsulin such as U-100. Aforementioned U.S. patent publication No.2012/0078170, U.S. provisional patent application Ser. No. 62/057,273and U.S. patent application Ser. No. 14/869,906 each also describepatient interaction with and use of infusion pumps such as the exemplaryinfusion pumps described herein.

As noted above, some ambulatory infusion pumps are intended to be wornon a belt, carried in a pocket, or otherwise supported within a holderof some kind (referred to collectively as “pocket pumps”). Such infusionpumps transfer fluid from a reservoir to an infusion set by way of anelongate tube. Subcutaneous access may be obtained by way of a cannulain the infusion set. Other ambulatory infusion pumps are intended to beadhered to the skin above the delivery site (sometimes referred to as“patch pumps”). Here, the cannula or other subcutaneous access devicemay extend directly from the infusion device. Given these modes of use,patients typically prefer the device to be as small as possible so it ismore comfortable, less obtrusive, and less visible. In addition,patients want a device that is easy and convenient to use.

An exemplary ambulatory infusion system, which is generally representedby reference numeral 100 in FIGS. 1A, 1B, and 2, includes a durableassembly 200 and a disposable assembly 300. Exemplary durable assembly200 includes a housing 202, one or more batteries or other energy supply221, one or more capacitors or other energy storage 222, amicroprocessor 223, a coil assembly 224 (which functions as a motorstator), and one or more Hall effect sensors 225. Exemplary disposableassembly 300 includes a baseplate 350 supporting components such as amagnetic motor rotor 331, a gear train 332 including lead screw drivegear 333 in a reservoir support block 337, and a lead screw 334 attachedto plunger 335, which is positioned in a medicament reservoir 336 thatis mounted to the reservoir support block 337. The exemplary plunger 335includes a core and a plurality of seals on the core. A cover 302, underwhich some or all of the magnetic motor rotor 331, gear train 332 (withdrive gear 333), lead screw 334, plunger 335, and medicament reservoir336 are located in various embodiments, may be mounted to the baseplate350.

The lead screw drive gear 333, lead screw 334, plunger 335, medicamentreservoir 336 and reservoir support block 337 may also be referred tocollectively as a “reservoir assembly.” Other exemplary reservoirassemblies that may be employed in, for example, infusion system 100 aredescribed below with reference to FIGS. 10-23.

The exemplary disposable assembly 300 may be secured to the exemplarydurable assembly 200, as shown in FIGS. 1A and 2. To that end, theexemplary housing 202 includes a top wall 204, bottom walls 206 a and206 b and a side wall 208 that together define a relatively thin housingportion 210 and a relatively thick housing portion 212. An indentation214 is formed in the relatively thick portion 212. The exemplary cover302 includes top walls 304 a and 304 b and a side wall 306 that togetherdefine a relatively thin cover portion 308 and a relatively thick coverportion 310. A portion of the baseplate 350 is not covered by the cover302, thereby defining a recess 312 that is bordered by a wall 314 thatextends around the baseplate (see also FIG. 4B). When the durable anddisposable assemblies 200 and 300 are secured to one another in themanner illustrated in FIG. 1A, the relatively thick portion 212 of thehousing 202 will reside in the recess 312 of the disposable assembly 300(with the wall 314 in the indentation 214). The relatively thin portion210 of the housing 202 will reside on the top wall 304 b of the cover302. The cover 302 also includes a projection 316 that mates with arecess 216 on the housing 202. Additionally, as is discussed in greaterdetail below, the disposable assembly 300 may be configured fordifferent medicaments, such as different medicament concentrations,different medicament amounts, or different modes of system operation.

In other implementations, the cover 302 may be configured to cover fewerthan all of the components on the baseplate 350. For example, a covermay be configured such that the magnetic motor rotor 331 and a portionof the gear train 332 are not under the cover, while the remainingcomponents are under the cover. In still other implementations, thecover 302 may be omitted and the durable assembly 200 may be configuredto cover all of the components on the baseplate 350. In yet otherimplementations, what is referred to in the present application as the“durable” assembly, may be disposable, resulting in a fully disposablesystem.

As discussed in U.S. patent publication No. 2012/0078170 describedabove, and in U.S. application Ser. No. 13/300,574, filed Nov. 19, 2011,and corresponding U.S. patent publication No. 2012/0184907, and in U.S.application Ser. No. 13/475,843, filed May 18, 2012, and correspondingU.S. patent publication number 2013/0138078, each of which areincorporated by reference in their entireties, ambulatory infusionsystems that employ a reservoir on a baseplate may be configured fordifferent types of use. For example, disposable assembly 300 may beadhered to the patient's skin and may be used in conjunction with acannula (not shown) that is operatively connected to the reservoir 336so that the system 100 may be deployed as a “patch-pump,” as shown inFIG. 2A. Alternatively, as shown in FIGS. 2B, the baseplate 350 ofdisposable assembly 300 may be configured to operably connect thereservoir 336 to an infusion set 382 (e.g., by way of the illustratedinfusion set tube and a connector 380 shown in FIGS. 1B and 2) so thatthe system 100 may be deployed as a “pocket pump,” a “belt-worn pump” orsome other wearable pump. In other words, using the same durableassembly 200, the user may configure the system for use as “pocket pump”or a “patch pump” by simply selecting the appropriate disposableassembly and attaching the disposable assembly to the durable assembly.The user may also switch from one configuration to another, by simplyremoving one disposable assembly and replacing it with anotherdisposable assembly.

It should therefore be noted that the present inventions include kitsthat contain various combinations of disposable assemblies, where atleast two of the disposable assemblies may be different. Additionally oralternatively, kits or other packages may include various disposableassembly components, such as an infusion set and/or cannula inserter.Kits may also include a durable assembly. The disposable assemblies insuch kits may also include the detection/identificationinstrumentalities discussed below. The components of the present kits(e.g., combination of various disposable assemblies and/or components)may be stored in a common package, with individual packages for eachcomponent if necessary, and provided to the user in the common package.Other components that may be provided in such kits include, but are notlimited to, inserters that are preloaded with a cannula, and cleaningswabs. A recharger may also be provided in a kit that includes a durableassembly.

In addition to disposable assembly packaging and labeling, the differentdisposable assemblies may include visual cues to differentiate thevarious disposable assemblies. For instance, disposable assemblies withdifferent concentrations of medicament or different medicament fillvolumes may use different colors for the reservoir and/or baseplate ofthe disposable assembly, or mechanical features that ensure disposablesare only able to attach to correctly programmed durables.

It should also be noted here that, but for the issue of priming, thedispensing procedures associated with an infusion system “patch pump”configuration, which may include a durable assembly 200 and a disposableassembly 300, are substantially the same as the dispensing proceduresassociated with a “pocket pump” configuration, which may also include aninfusion set 382 (see FIGS. 2B). With a “patch pump” configuration,priming is not necessary because the volume of the associated cannulawill be very small and there is a direct connection between the cannulaand the medicament reservoir. Priming is, however, required to fill theinfusion set tube (FIG. 2B) in a “pocket pump” configuration prior tothe onset of medicament delivery. For instance, 20-30 μl may be requiredto fill the entire infusion set tube and, accordingly, the primingprocedure may involve the rapid delivery of 10-15 IUs of U-500 insulinto the tube. The present inventors have determined that it would beadvantageous to prevent users from initiating a priming procedure whenthe system is in the “patch pump” configuration, with a cannulapositioned to deliver medicament essentially directly from themedicament reservoir to the patient, because rapidly delivering 10-15IUs of insulin to the patient could adversely affect patient health.

To prevent such undesirable outcomes, and for user convenience in othersituations involving the choice between a variety of disposableassemblies (such as disposable assemblies with reservoirs containingdifferent medicaments, different concentrations of a medicament, and/orvarying amounts of medicaments), at least some of the present disposableassemblies may be provided with a baseplate identification device and atleast some of the present disposable assemblies may be provided withstructure that cooperate with a baseplate identification device in sucha manner that the durable assembly microprocessor/controller can make a“baseplate type” determination. Exemplary baseplate identificationinstrumentalities and methodologies may be as described inaforementioned U.S. patent publication Nos. 2012/0078170, 2012/0184907,and 2013/0138078. In addition, baseplate identification may be performedmechanically. For instance, a pin or rib may prevent attachment ofcertain disposable assemblies with certain durable assemblies.Additionally or alternative, certain durable assemblies will simply notfunction with certain disposable assemblies.

Alternatively, the patient or a clinician may program the system, suchas via a remote control, to indicate the type of disposable assemblyattached. In a manner such as this, a patient can access a variety ofmedicaments for use with a single durable assembly.

Once the “baseplate type” determination is made (e.g., “patch pump”disposable assembly 300 versus a “pocket pump” with infusion set 382attached), the durable assembly will proceed in a manner, or mode ofoperation, that is appropriate for the attached disposable assembly. Forexample, if “patch pump” disposable assembly 300 is detected, thedurable assembly controller will not include priming as part of thedelivery process and, in some implementations, will prevent the userfrom manually implementing a priming procedure. If, on the other hand, a“pocket pump” disposable assembly is detected, then the delivery processmay include appropriate priming of the infusion set tube.

Whether configured as a “pocket pump” or a “patch pump,” the system maybe configured to provide basal delivery of medicament in accordance witha delivery profile provided by a physician by way of a clinician'sprogramming unit. For example, the system may include a program thatstores a number of delivery profiles (e.g., delivery profiles associatedwith a 24-hour delivery cycle, delivery profiles for particularsituations such as sleep or illness, and the like). Each deliveryprofile specifies multiple doses (or pump “operations”) over time, e.g.,a particular number of doses at particular times or a particular numberof doses per unit time. In some implementations, a dose may be thevolume associated with the minimum controllable displacement of theplunger 335. The system may also be configured to provide bolus deliveryin response to an instruction from a patient remote control 1000 (FIG.2A). A bolus instruction may come in response to a high glucose levelmeasurement in the case of a diabetic patient, an increase in pain levelin the case of a pain management patient, or some other symptom. Thesystem may also be configured to perform other functions, such as endingmedicament delivery in response to instructions from patient remotecontrol 1000.

The present infusion pumps may be used in conjunction with a widevariety of remote controls. Such remote controls may be used to, forexample, allow the user to transmit instructions to the durable assembly200 or facilitate communication between durable assembly 200 and theuser (e.g., an alarm condition message or other message concerning theconditions of system 100). An exemplary remote control 1000 (FIG. 2A)may be configured to facilitate one, some, or all of the followingoperations: (1) turning the remote control 1000 on or off, (2)associating (or “assigning”) the remote control 1000 to the durableassembly 20, (3) obtaining status information such as medicament level,battery charge level, and/or alarm conditions, (4) silencing the durableassembly alarm, (5) selecting options that may be associated with thedurable assembly alarm such as type of alarm (audible, palpable, and/orvisible) and strength/volume of alarm, (6) connecting remote control1000 to a computer to, for example, update remote control or durableassembly firmware, load and delete delivery profiles stored in thedurable assembly or remote control, and otherwise reprogram the durableassembly or remote control, (7) selecting medicament options such asmedicament concentrations, (8) selecting and initiating a storedmedicament delivery profile, (9) increasing and decreasing medicamentdose rate, and/or (10) pausing a dispensing operation. A user may pausedelivery in order to remove or replace a patient applied structure(e.g., a disposable assembly), adjust for a current or anticipatedchanged body condition (e.g., low glucose, vigorous exercise), follow aphysician's suggestion, or disconnect the durable assembly from the bodyfor any other reason.

The exemplary remote control 1000 (FIG. 2A) may be configured togenerate an indicator, based on information from a microprocessor 223for durable assembly 200, that is indicative of, for instance, theamount of time remaining in the current dispensing program, the amountof time until the next disposable assembly replacement, etc. Theindicator may be audible, visible, palpable, or combinations thereof. Atime remaining indicator may be useful for a variety of reasons. Forexample, knowledge of the time remaining prior to next disposableassembly replacement allows the patient to determine, based at least inpart on the current time of day and upcoming events (e.g., travel orsleep), whether or not it would be more convenient to replace thedisposable assembly at a time prior to the end of the dispensingprogram.

As described above, parts of the present systems may be considered thereusable parts, while other parts may be considered the disposableparts. In the illustrated embodiments, the durable assembly 200, whichmay include structures such as microprocessor 223 and coil assembly 224,is reusable, while exemplary disposable assemblies 300, which mayinclude structures such as a motor rotor 331 and reservoir 336 on abaseplate 350, are disposable.

With respect to dimensions, some embodiments of the exemplary infusionpump system 100 may have the following dimensions: length dimensions of35 mm+/−1.0 mm, 35 mm+/−0.10 mm, or 35 mm+/−5.0 mm; width dimensions of30 mm+/−1.0 mm, 30 mm+/−0.10 mm, or 30 mm+/−5 mm; and overall thicknessor height dimensions of 8.5 mm+/−1.0 mm, 8.5 mm+/−2 mm, or 8.5 mm+/−0.10mm. Suitable housing materials include, but are not limited to, plasticor other materials having a modulus of elasticity of 0.2-1.0 millionpsi.

Exemplary durable assembly microprocessors and associated circuitry;rechargeable batteries and associated battery rechargers and rechargingmethods; battery and recharging management; temperature sensors; andexemplary alarms and alarm conditions are described in more detail inaforementioned U.S. patent publication Nos. 2012/0078170, 2012/0184907,and 2013/0138078.

Turning now to FIGS. 3A and 3B, an exemplary durable assembly 200 mayinclude a power source such as one or more batteries 221, temporarypower storage such as one or more capacitors 222 (see FIGS. 2 and 5B), acontroller such as microprocessor 223, a coil assembly 224, and a halleffect sensor 225. Those of skill in the art will appreciate thatincluding the motor's coil assembly 224 and all other electronics withinthe durable assembly 200 reduces the cost and complexity of disposableassembly 300. In addition, the microprocessor 223 provides flexibilityto include features such as user data storage, programs,programmability, adjustability, a display, buttons, wirelesscommunication protocols, or the like to the pump 100. Durable assembly200 may also be molded with locking features that snap onto thedisposable assembly 300, but that also allow removal of the durableassembly 200 from the disposable assembly 300 either while thedisposable assembly remains in place on the patient (after medicamentdelivery has been paused), or after the entire system has been removedfrom the patient.

The power source may be one or more commercially available batteries,such as a commercially available zinc-air battery or lithium polymerbattery. The batteries may be selected to have sufficient capacity tooperate the system for certain delivery amounts or delivery times, suchas for over 400 units of delivered insulin. The optional power storagemay be one or more commercially available capacitors or super-capacitorsor other temporary storage device(s).

Turning now to FIGS. 4A and 4B, an exemplary disposable assembly 300 mayinclude baseplate 350 and components such as a reservoir 336, a plunger335 within the reservoir and connected to lead screw 334, and a magneticmotor rotor 331 mechanically attached through gear train 332 to affectrotation of the lead screw drive gear 333, which causes translation ofthe lead screw 334 and plunger 335 within reservoir 336. The cover 302is positioned over these components in the illustrated embodiment. Theexemplary baseplate 350 includes an adhesive backing for attachment tothe patient with a removable adhesive cover. The baseplate 350 may alsobe molded with baseplate locking features that snap onto the durableassembly 200 (such as magnets molded into the housings of eachassembly), and that also allows removal of the durable assembly 200 fromthe disposable assembly 300.

Referring to FIGS. 2 and 4B, the exemplary reservoir 336 includes abarrel 338 with an inner surface 340 defining a fluid storage volume 342and an oval cross-section, but other shapes (such as circular) arepossible as is discussed below with reference to FIGS. 10-23. A plunger335 with a matching cross-sectional shape fits within the barrel andcarries a fluid seal such as, but not limited to, o-rings, to seal themedicament within the storage volume 342. The exemplary plunger 335 isformed from rubber and includes three o-ring seals. The reservoir 336includes a connector 380 that may be used for filling reservoir 336, orfor attaching a cannula for “patch-pump” type configurations, or forconnecting (potentially via an appropriate adapter(s)) an infusion setfor “pocket-pump” type configurations. The plunger 335 moves within thebarrel 338 to vary the volume of medicament within the storage volume342. Reservoir 336 may be, for instance, prefilled (or user-filled) withU-500 insulin in various volumes to suit the patient use profile. Inother instances, lower concentrations of insulin, such as U-100 insulinand U-200 insulin, may be employed. A plug may be inserted in theconnector 380 to maintain a sterile environment until use. The patientwould remove the plug prior to use, in those instances.

Additional exemplary baseplates for use with the disposable assembliesof the present inventions, as well as exemplary cannula designs, fluidicconnection between a medicament reservoir and the cannula, cooperationbetween the cannula and disposable assemblies (for instance, to preventaxial movement of the cannula relative to the baseplate and patient),attachment of an infusion set to the reservoir of the disposableassembly, configurations and uses of a non-delivery baseplate,arrangements and structures for attaching disposable and durableassemblies, skin adhesive designs, and various occlusion sensors, may beas described in U.S. patent application Ser. No. 12/890,207, filed Sep.24, 2010 and corresponding U.S. patent publication number 2012/0078170,as well as aforementioned U.S. patent publication Nos. 2012/0184907 and2013/0138078.

Turning now to FIGS. 5A-5C and the illustrated two-piece motor, themotor's coil assembly 224 (and a Hall effect sensor 225) of the durableassembly 200 are positioned above the magnetic motor rotor 331 that ispart of the disposable assembly 300. An exemplary multi-pole motor rotor331 may be disc-shaped and have a 9.8 mm outer diameter, 5.2 mm innerdiameter, and 0.8 mm thickness. Another example motor rotor may have an11 mm outer diameter, 5 mm inner diameter, and 1.2 mm thickness.Multi-pole motor rotors of this type typically cost less than 5 centsper piece, helping control the total cost of disposable assembly 200.The motor rotor 331 is also parallel to the baseplate 350, i.e., themotor rotor axis of rotation is perpendicular to the baseplate, in theillustrated embodiment. The microprocessor 223 directs rotation of motorrotor 331 by sequentially energizing the coils of motor coil assembly224 to create an electromagnetic torque coupling between the motor coilassembly 224 and the motor rotor 331. The position/orientation of therotor's poles relative to the rotating magnetic field generator (coilassembly 224) is measured by back EMF, a rotary encoder, a hall effectsensor 225 (FIG. 5A), or the like. For instance, a Hall effect sensormounted on the coil windings may be used to supply the microprocessor acount, a tachometer signal, or rotor position, allowing low-costclosed-loop control of the rotor speed. Brushless motors of this typeare typically 85-90% or more efficient, and run very cool. While theremay be variations in construction, the face-to-face stator coils andflat rotor plate shown in FIGS. 5A-5C provide a compact design. Inaddition, more coils and/or Hall effect sensors may be used.

As can best be seen in FIG. 6, between the motor coil assembly 224 andmotor rotor 331 is a gap 240. Some or all of the gap 240 may be definedby (and occupied by) portions of the housing 202 and the cover 302,i.e., the housing bottom wall 206 a and the cover top wall 304 b in theillustrated implementation. In other implementations, the gap 240between the between the motor coil assembly 224 and motor rotor 331 maybe occupied by only a portion of the durable assembly housing, or only aportion of the disposably assembly cover, or no structure at all and maysimply be an air gap. The size of the gap, which is defined by thedistance between the motor coil assembly 224 and the motor rotor 331, istypically about 0.5 mm to 2.0 mm. As such, there is no gear engagementor other mechanical connection between the durable assembly 200 anddisposable assembly 300. And as described earlier, all electronics maybe positioned within the durable assembly 200, with the energy needed bythe disposable assembly 300 transferred by electromagnetic torquecoupling, which is a coupling without direct mechanical coupling orelectrical contact from the durable assembly 200. This exemplary designaffords the additional advantage of being relatively simple to makewaterproof, or at least water resistant.

As described above, rotation of motor rotor 331 drives gear train 332,causing rotation of lead screw drive gear 333, which in turn affectstranslation of the lead screw 334 and plunger 335, which is attached tolead screw 334. In this manner, electromagnetically generated torque iscreated when electromagnetic energy supplied by durable assembly 200 istransformed into mechanical forces within the disposable assembly 300that advance plunger 335. A ratchet (not shown) or other similar devicemay be used to prevent back drive of gear train 332. As plunger 335 isdriven through reservoir 336, medicament is dispensed precisely,corresponding to the precision movements of the gears and motor rotor.With the entire gear train, lead screw drive gear, lead screw, andplunger all permanently contained in the disposable assembly 300, thereis no need to retract any plunger components into the durable assembly200 prior to separation from the disposable assembly 300. As a result, afurther advantage of this exemplary design is greatly reduced energyconsumption, which allows use of, for instance, a primary battery(ies)as a power source.

Use of an exemplary system 100 will now be described. At the most basiclevel, a patient's use of the exemplary infusion pump systems (e.g.,system 100 in FIGS. 1A-2B) involves obtaining a new disposable assembly300, connecting the disposable assembly to the durable assembly 200,peeling the liner from the baseplate adhesive layer, gainingsubcutaneous access, and initiating a medicament delivery operation. Insome instances, use may involve additional steps such as attaching acannula to connector 380 of the disposable assembly and removing acannula cap, if necessary. Various aspects of the basic operation of thepresent systems are described below. Operation of a system does notnecessarily require all of the steps each time the system is deployed,and the order of some of the steps may be changed. Operation is alsodiscussed below, in the exemplary context of the above-described durableassembly 200 and disposable assembly 300 used as a patch pump, throughthe use of a flow chart (FIG. 8). The discussion is, however, equallyapplicable to other patch pump implementations, as well as to pocketpump implementations with minor variations. Also, unless otherwiseindicated, the actions and determinations performed by the durableassembly 200 are controlled by the durable assembly microprocessor andfurther references to the controller are limited in the interest ofbrevity.

Referring to FIG. 8, use of the present systems may involve removal of adisposable assembly from a durable assembly and the replacement of thedisposable assembly. This may occur when the medicament reservoir isempty (as described in more detail in U.S. patent application Ser. No.12/890,207 and corresponding U.S. patent publication number2012/0078170) (Step 5101) and a “replace disposable assembly” message oralert is presented (Step S102), or when the durable assembly controllerreceives a user-initiated “replace disposable assembly” signal from aremote control 1000 (Step S103). The user may desire to replace adisposable assembly before the medicament reservoir is empty for avariety of reasons such as, for example, to accommodate the user's sleepor travel schedule, when the medicament exhibits a loss ofeffectiveness, when a dispensing problem arises, or due to a prescribedchange in medicament.

The user may then obtain, possibly from storage in a refrigeratordepending on medicament requirements, a new pre-filled disposableassembly 300 or may then obtain a new disposable assembly and fill thedisposable assembly with medicament (Step S104). The durable assembly200 and disposable assembly 300 may then be removed from the skin,separated, and the disposable assembly 300 discarded (Steps S106 andS107).

Next, the new disposable assembly 300 may be attached to the durableassembly 200 (Step S109). The user should clean the skin surface S ontowhich the baseplate 350 of disposable assembly 300 will be adhered (FIG.7, and Step S116 of FIG. 8). Then the user peels off the baseplateadhesive liner to expose the baseplate adhesive layer (Step S117) andremoves cannula cap (when present) (Step S118). In the exemplary use ofFIG. 8, the disposable assembly 30 is supplied with a cannula in fluidcommunication with the reservoir storage volume. In other embodiments, acannula inserter may be attached to the system, which may be triggeredto insert the cannula after the system is placed against the skin.Exemplary inserters are described in U.S. patent publication number2013/0138078.

Returning to the steps in FIG. 8, the system 100 including durableassembly 200 and disposable assembly 300 may be positioned over asuitable body location and pressed gently to adhere the adhesive layerto the skin surface S and, once the system has been adhered (Step S119),the inserter may be actuated to position the end of a cannula below theskin. It should be noted that in those implementations which do notinclude an inserter, and instead simply include a hollow needle (or acannula and removable trocar arrangement) that projects outwardly fromthe bottom surface of the system, the user need only adhere the adhesivelayer to position the needle or cannula below the skin. The trocar, ifemployed, may then be removed. Finally, if necessary, the remote control1000 may be used to initiate a particular medicament delivery operation(Step S120). The delivery operation may follow a predetermined deliveryprofile (e.g. a particular basal rate, a series of time-spaced bolusdeliveries, or some combination thereof) that is equated to motor rotorrotations, at particular rates and times, required to deliver medicamentin accordance with the profile. Alternatively, the profile may be inputby the user with the remote control 1000 and stored by the durableassembly microprocessor. For example, the remote control may store anumber of different delivery profiles and bolus deliveries from whichthe patient can choose. Such profiles may correspond to, for example anddepending on the medicament, days where vigorous exercise is expected,days where it is not, incidences of increased pain, etc. Alternatively,or in addition, the profile stored in the durable assemblymicroprocessor may be set by a clinician's programming unit. In such acase, as in the case of different disposable assemblies 300 providedwith different specified delivery rates, a remote control may not beneeded to initiate, e.g., basal delivery. The discussion above is alsoapplicable to use of the “pocket pump” system as shown in FIG. 2B. Minorvariations in the above-described procedure include, for example, use ofan infusion set 382 instead of a cannula, attaching the infusion set toconnector 380, potentially via an adapter (which may vary with the typeof infusion set 382), and priming of the infusion set tube.

Another exemplary ambulatory infusion system, which is generallyrepresented by reference numeral 100 a in FIG. 9, includes a durableassembly 200 a and a disposable assembly 300 a. System 100 a issubstantially similar to system 100. Here, however, the intersection ofthe top walls is primarily linear. Additionally, the disposable assembly300 a has a recess 316 a which mates with a corresponding projection 216a on the durable assembly 200 a. The projection 216 a and recess 316 aare located at the outer perimeter of the assembled system 100 a.

The reservoirs may also be, but are not required to be, prefilled.Prefilled reservoirs are advantageous for a variety of reasons. By wayof example, but not limitation, some users prefer to avoid reservoirfilling procedures because they are inconvenient and tend to involveneedles. User-based refilling also increases the likelihood that airbubbles will be introduced into the reservoir, while prefilling by themanufacturer of the reservoir and/or the medicament can be accomplishedwithout any substantial introduction of air bubbles using, for example,a vacuum filling procedure. Nevertheless, user-filled reservoirs may beemployed in some instances. A variety of exemplary medicamentreservoirs, including those that include pressure sensors (such as forsensing occlusion) and other sensors, are described in more detail inaforementioned U.S. patent publication Nos. 2012/0078170, 2012/0184907,and 2013/0138078.

While a prefilled reservoir would greatly improve the ease of use ofpatch and pocket pump technology, there are several challenges toproviding such prefilled reservoirs. By way of example but notlimitation, long-term storage of insulin has traditionally used glasscontainers with bromobutyl rubber stoppers, and this has been applied toprefilled insulin pens using glass syringe barrels with bromobutylplungers. The high coefficient of friction of bromobutyl on glassrequires a coating of silicone oil on the interior of the reservoir, sothe plunger may slide easily in the barrel during dispensing.

While successful in pens, this combination has several drawbacks,especially for low-cost patch and pocket pumps. For instance, glass isprone to fracture and flaking. In addition, glass is costly when tighttolerances must be maintained (e.g., for accurate dispensing from asmall reservoir). Also, bromobutyl rubber compositions must be carefullycontrolled to prevent medicament contamination. Furthermore, siliconeoil coatings require careful, controlled application, and occasionallyresult in medicament contamination. Although properly controlledapplication of silicone oil lowers the plunger “glide force” (, alsoreferred to as “running force,” based on dynamic friction), the siliconeoil tends to “squeeze out” from the sealing zone between the glassreservoir barrel and the rubber stopper/plunger over time, resulting inhigh “break force” (, also referred to as “break-out force,” based onstatic friction) during startup. Additionally, the glide force is quitevariable within a single reservoir and the glide force and break forceare quite variable from reservoir to reservoir (i.e., betweenreservoirs).

Accordingly, these glass/rubber/silicone oil based systems need to bedesigned to generate a high “break force” yet operate with a low “glideforce”. This results in more complex, larger, and more costly pumpingsystems.

As these materials were extended from insulin pens to prefilledreservoirs, attempts were made to replace the glass with cyclic olefinpolymer (COP) or cyclic olefin copolymer (COC) and to replace thesilicone oil layer with specialty coatings, such as Teflon and parylene,on the rubber plunger. While these coating materials achieved the goalof lowering the high coefficient of friction of rubber on COP/COC, thelong-term stability of insulin solutions was compromised by water vapormigration out of the insulin solution and past the seal created by thecoated rubber plunger. In a small, prefilled pump, such as a patch pumpcontaining 400 microliters of insulin, the water lost from the insulinsolution must be less than a few microliters per year. This ischallenging with the configurations above.

A solution to this challenge is provided with a dual seal system. Eachseal type has a distinct function and can therefore be designed ideallyfor that use. A first seal type is a static seal. When the pump is instorage, this seal minimizes water vapor loss. As will be seen below,this seal may be fixed into position within the reservoir assemblysupport block or on the plunger core. Since the static seal onlyfunctions during storage, it can be designed to function with relativelylarge contact stresses and soft, sticky materials, such as bromobutylrubber, to seal against water vapor loss. A second seal type is adynamic seal. This seal is designed as a low glide/break force seal thatoperates when the plunger is moving during dispensing, but it also mustbe compatible with long term insulin storage. When dispensing commences,the static seal automatically disengages, minimizing the forces requiredto move the plunger during dispensing.

Turning now to FIGS. 10-13, the exemplary pump reservoir assembly 400illustrated therein, which may be employed in the exemplary ambulatoryinfusion system 100 described above or other infusion systems, includesa lead screw 434 engaged to a lead screw drive gear 433 and attached toplunger 435, which is positioned in a medicament reservoir 436. Thereservoir 436 includes a barrel 438 with an inner surface 440 defining afluid storage volume 442. The reservoir barrel 438, which may be formedfrom COP, COC, or the like, to maintain medicament (e.g., insulin)stability, is bonded or otherwise attached to support block 437 afterthe interior components (e.g., lead screw drive gear 433, lead screw434, and plunger 435) are assembled. The end of the reservoir barrel 438includes a connector 480.

The exemplary plunger 435 includes a plunger core 460 that is bonded orotherwise attached to lead screw 434 and carries at least one dynamicseal 462 that is in contact with the inner surface 440 of the reservoirbarrel 438, where the plunger core 460 has an outer surface diameter andthe inner surface 440 has an inner surface diameter. Plunger core 460may be made of a relatively rigid material such as COP, COC, or thelike, to maintain medicament (e.g., insulin) stability, and the dynamicseal(s) 462 may be made of a low friction resilient material, such aslow friction plastic, parylene-coated rubber, Teflon-coated rubber,silicone-coated rubber, or the like. In the illustrated implementation,the dynamic seals 462 are o-ring seals. The plunger 435 slides withinreservoir barrel 438 to dispense medicament. As described above in thecontext of infusion system 100, drive gear 433 rotates from torquesupplied by a drive mechanism, such as magnetic motor rotor 331 and agear train 332 in FIG. 2, to cause translation of the plunger 435.

As shown in FIGS. 10 and 13, the exemplary plunger 435 is in the “fullposition” when no medicament has been dispensed and the reservoir 436 isfull. This may also be called the storage position, since the reservoir436 is generally full during storage. The reservoir assembly 400 (aswell as reservoir assemblies 400 a and 400 b (discussed below) may alsobe user-filled. In some instances where the reservoir assembly isuser-filled, the plunger 435 will initially be located adjacent to theconnector 480 and will move, in a direction opposite the dispensingdirection, from there to the full position as the reservoir 436 isfilled.

When plunger 435 is in this full/storage position, at least one radialstatic seal 464 engages plunger core 460 to affect a static vapor seal.Radial static seal 464 may have various cross-sectional shapes and beattached to support block 437 in various ways. For instance, radialstatic seal 464 may be an O-ring having a static seal inner diameter anda static seal outer diameter. As another example, rather than fittinginto a recess in support block 437, as shown in FIGS. 12 and 13, radialstatic seal 464 may be an O-ring that fits into an O-ring groove. In anycase, the vapor seal may be achieved via an interference fit betweenradial static seal 464 and a static sealing surface 466 of plunger core460. To achieve a seal via interference fit, radial static seal 464 mayhave a static seal inner diameter that is smaller than the outerdiameter of the static sealing surface 466. The sealing surface 466 ofplunger core 460 that is engaged by static seal(s) 464 may be designedto aid the vapor seal. For instance, this sealing surface 466 may be aslightly protruding circular surface. The interference between theplunger core sealing surface 466 and the radial static seal 464 causeselastomeric deformation of the seal 464 to create a vapor seal.

As shown in FIGS. 14 and 15, during dispensing of medicament, theplunger 435 moves in a dispensing direction away from the full position(FIGS. 10 and 13). For instance, in the orientation used for FIGS. 14and 15, the plunger 435 translates left as medicament is dispensed. Whendispensing begins, the plunger 435 begins to translate left and thesealing surface 466 of the plunger core 460 slides off the radial staticseal(s) 464.

As will be appreciated by those of skill in the art, the plunger 435automatically disengages from the static vapor seal(s) 464, whilecontact between the dynamic seal(s) 462 and the inner surface 440 of thereservoir barrel 438 is maintained, when the plunger moves out of thefull position (or “storage position”); that is, no additional steps oractions are required to deactivate the static vapor seal(s) 464 whilethe dynamic seal(s) 462 remain active, to separate sealing surface 466from static seal(s) 464 while the dynamic seal(s) 462 remain in contactwith the barrel inner surface 440, or to allow dispensing to begin. Putanother way, the static vapor seal(s) 464 and the plunger 435 aredisengaged from one another in response to a predetermined amount ofmovement of the plunger 435 in the dispensing direction out of the fullposition. The movement of the plunger 435 in the dispensing directionresults in the static seal(s) 464 coming out of contact with the surfaceto which it is engaged to prevent vapor migration. In addition, thestatic seal(s) 464 are stationary; static seal(s) 464 do not need tochange position in order for dispensing to begin or for the plunger 435to move out of the full/storage position. As will also be appreciated bythose of skill in the art, similar results may be obtained if the staticseal(s) 464 are instead positioned on the plunger core 460 (forinstance, around surface 466 of plunger core 460), so that the sealingsurface is instead on support block 437. Here too, movement of theplunger 435 in the dispensing direction results in the static seal(s)464 coming out of contact with the surface to which it is engaged toprevent vapor migration. In either case, radial static seal(s) 464 maybe made of bromobutyl rubber or other relatively soft sealing material,for excellent long-term water vapor loss.

To lower contact forces and minimize friction to, in turn, lowerbreak-out forces required to move away from the full/storage position,while still achieving acceptable sealing, the diameter of the sealingsurface 466 of plunger core 460 may be kept as small as possible. Whenthe static seal(s) 464 are engaged before dispensing begins, the radialsealing contact at sealing surface 466 provides an excellent vapor seal,which is especially important for long-term storage. Since the staticseal(s) 464 are not engaged during dispensing, a low plunger 435 glideforce may be achieved. This results in reduced energy consumption, whichallows use of, for instance, primary battery(ies) as a power source.This is well suited to infusion systems that benefit from energyefficiency, such as the exemplary ambulatory infusion system 100described above with reference to FIGS. 1A, 1B, and 2, since it isdesirable to use no more energy than is actually needed.

Other embodiments of a dynamic seal combined with a static seal thatdisengages when dispensing commences, resulting in reduced forces andenergy requirements, are possible. For instance, the exemplary reservoirassembly 400 a illustrated in FIGS. 16-19 is substantially similar toreservoir assembly 400 and similar elements are represented by similarreference numerals. Here, however, the dynamic seals may be integralwith the plunger core. To that end, the exemplary plunger 435 a includesa plunger core 460 a that may be molded or machined from a relativelyrigid material (e.g., COP, COC, or the like) and includes integralsealing ridges 462 a to achieve the dynamic seal. To ensure a sealbetween sealing ridges 462 a and the inner surface 440 of reservoirbarrel 438, a radial energizing spring 468 may be positioned withinplunger core 460 a. The radial energizing spring 468 radially deformsplunger core 460 a to force sealing ridges 462 a into a low friction,sealing contact with the inside surface 440 of reservoir barrel 438.

The exemplary static seal 464 a may be one or more face-type staticseals that engage(s) the rear surface of plunger core 460 a when nomedicament has been dispensed, the reservoir 436 is full (e.g., duringstorage), and the plunger 435 a is in the “full position” or “storageposition”. Static face seal 464 a may be made of bromobutyl rubber orother low-water-vapor-transmitting elastomers, for excellent long-termwater vapor loss prevention. When plunger 435 a is in the full position,the static face seal 464 a and the rear surface of plunger core 460 aare in contact, resulting in a vapor seal. In the example shown in FIG.16, this seal is formed between the static face seal 460 a and a staticsealing surface 470 on the plunger core 460 a.

As the plunger 435 a slides within reservoir barrel 438 to dispensemedicament, the plunger 435 a moves away from the full/storage position,i.e., translates left (in the illustrated orientation) as medicament isdispensed. When dispensing begins, the plunger 435 a begins to translateleft (FIG. 19), and the sealing surface 470 of the plunger core 460 aloses contact with static face seal(s) 464 a. As will be appreciated bythose of skill in the art, the plunger 435 a automatically disengagesfrom the static vapor seal(s) 464 a, while contact between the dynamicseal(s) 462 a and the inner surface 440 of the reservoir barrel 438 ismaintained, when the plunger moves out of the full position (or “storageposition”); that is, no additional steps or actions are required todeactivate the static face seal(s) 464 a while the dynamic seal(s) 462 aremain active, to separate static seal 464 a from static sealing surface270 while the dynamic seal(s) 462 a remain in contact with the barrelinner surface 440, or to allow dispensing to begin. In addition, thestatic seal 464 a is stationary; static seal 464 a does not need tochange position in order for dispensing to begin or for plunger 435 a tomove out of the full/storage position. Put another way, the static vaporseal(s) 464 a and the plunger 435 a are disengaged from one another inresponse to a predetermined amount of movement of the plunger 435 a inthe dispensing direction out of the full position.

Because static seal 464 a is not engaged during dispensing, the glideforce required to translate plunger 435 a during dispensing isdetermined by the choice of materials for the reservoir barrel 438,plunger core 460 a (when the dynamic seals are integral sealing ridges462 a), and the strength of radial energizing spring 468. As will alsobe appreciated by those of skill in the art, similar results may beobtained if static seal(s) 464 a are instead positioned on the back sideof the plunger core 460 a (i.e., the surface of plunger core 460 a thatfaces support block 437 a), so that the sealing surface is instead onthe surface of support block 437 a that faces the back surface ofplunger core 460 a.

When the plunger 435 a translates left (in the illustrated orientation)as dispensing begins, the static sealing surface 470 of plunger core 460a loses contact with static face seal 464 a with minimal break-forcerequired. In some instances, however, it may be desired to include ahelper spring to assist disengagement of the plunger 435 a from thestatic face seal 464 a (or from radial static seal 464), or to aid thebreak force required for dynamic sealing ridges 462 a (or for dynamicseal(s) 462), or to help with some combination of these. To that end,and referring to FIGS. 20-23, the exemplary reservoir assembly 400 b issubstantially similar to reservoir assembly 400 a and similar elementsare represented by similar reference numerals. Here, however, a helperspring 472 provides a force in just the small fraction of the distancethat the plunger 435 a travels through a reservoir barrel 438, such asonly in about the first 1 mm, and then may lose contact with the plunger435 a. The helper spring 472 may be a disk spring (a.k.a., conicalspring, conical washer, or Bellville spring). Multiple other springtypes are possible, such as a coil spring, leaf spring, helical lockwasher, curved washer, wave spring (a.k.a., wave washer or wavy washer),other compression spring or torsion spring, or the like.

Other positions for helper spring 240 (or similar spring that performsthe same function) are also possible. For instance, a helper springcould be attached to a different portion of support block 437 and engagea different surface of plunger 435 a. In other cases, a helper springcould be positioned on the back surface of plunger 435 a and pushagainst a surface on support block 437. In addition, as alluded toabove, the helper spring can work with other types of static vaporseals, such as radial static seal 464, and/or with other types ofdynamic seals, such as seal(s) 462. Furthermore, in some face-sealdesigns, the natural compressive elasticity of the seal may act as aspring trying to push the plunger 435 a out. In such a case, the staticface seal may act as the helper spring at an interface between thestatic sealing surface 470 and the static face seal 464 a.

Use of a static seal(s) to address water vapor loss, in conjunction withseparate dynamic seal(s) that are active during dispensing, allowsoptimization of the materials and material properties desired for thesealing surfaces, rather than trying to achieve both acceptable glideforces during dispensing and low water vapor loss during storage withjust one type of sealing surface. Further, use of a static seal thatautomatically disengages when dispensing commences reduces the torque,and thus the energy, required to commence and continue dispensing. Thus,excellent dynamic sealing properties and excellent long-term staticsealing properties may be achieved, while also conserving energy.

Various methodologies and systems are presented here in the context ofthe exemplary structures described in the preceding sections, andillustrated in the various figures, for the purpose of explanation only.Although the present methodologies and systems may employ the structuresdescribed above, they are not limited thereto. Additionally, embodimentsof the present inventions may incorporate any one, combinations of lessthan all, or all of the methodologies or devices referenced above.

Although the inventions disclosed herein have been described in terms ofthe preferred embodiments above, numerous modifications and/or additionsto the above-described preferred embodiments would be readily apparentto one skilled in the art. By way of example, but not limitation, thepresent reservoir assemblies may be incorporated into fully disposableinfusion pumps. It is intended that the scope of the present inventionsextends to all such modifications and/or additions and that the scope ofthe present inventions is limited solely by the claims set forth belowor later added.

Finally, with respect to terminology that may be used herein, whether inthe description or the claims, the following should be noted. The terms“comprising,” “including,” “carrying,” “having,” “containing,”“involving,” and the like are open-ended and mean “including but notlimited to.” Ordinal terms such as “first”, “second”, “third,” do not,in and of themselves, connote any priority, precedence, or order of oneelement over another or temporal order in which steps of a method areperformed. Instead, such terms are merely labels to distinguish oneelement having a certain name from another element having a same name(but for the ordinal term) to distinguish the elements. “And/or” meansthat the listed items are alternatives, but the alternatives alsoinclude any combination of the listed items. The terms “approximately,”“about,” “substantially” and “generally” allow for a certain amount ofvariation from any exact dimensions, measurements, and arrangements, andshould be understood within the context of the description and operationof the invention as disclosed herein. Terms such as “top,” “bottom,”“above,” and “below” are terms of convenience that denote the spatialrelationships of parts relative to each other rather than to anyspecific spatial or gravitational orientation. Thus, the terms areintended to encompass an assembly of component parts regardless ofwhether the assembly is oriented in the particular orientation shown inthe drawings and described in the specification, upside down from thatorientation, or any other rotational variation therefrom.

What is claimed is:
 1. An infusion pump reservoir assembly, comprising:a medicament reservoir comprising a reservoir barrel with an innersurface; a plunger moveable within the medicament reservoir in adispensing direction from a full position; and a static seal thatengages a sealing surface of a rear surface of the plunger that faces ina direction opposite the dispensing direction when the plunger is in thefull position, wherein the plunger and static seal are respectivelyconfigured and positioned relative to one another such that the staticseal is disengaged from the sealing surface of the rear surface of theplunger in response to movement of the plunger in the dispensingdirection from the full position, and a static seal inner diameter ofthe static seal is smaller than an outer diameter of the sealingsurface.
 2. The infusion pump reservoir assembly of claim 1, wherein theplunger defines an outer surface diameter that is greater than or equalto a static seal outer diameter of the static seal.
 3. The infusion pumpreservoir assembly of claim 1, wherein the static seal establishes aninterference fit with elastomeric deformation with respect to thesealing surface when the plunger is in the full position.
 4. Theinfusion pump reservoir assembly of claim 1, wherein the static seal isa static vapor seal.
 5. The infusion pump reservoir assembly of claim 1,wherein the static seal is stationary.
 6. The infusion pump reservoirassembly of claim 1, wherein the static seal is a face seal.
 7. Theinfusion pump reservoir assembly of claim 1, wherein the plungerincludes a core integral with a dynamic seal, and the dynamic sealremains in contact with the inner surface of the reservoir barrel as theplunger moves in the dispensing direction.
 8. The infusion pumpreservoir assembly of claim 1, further comprising: a helper springconfigured to assist disengagement of the plunger from the static seal.9. The infusion pump reservoir assembly of claim 1, wherein the plungercomprises a radial energizing spring configured to radially deform atleast a portion of the plunger.
 10. The infusion pump reservoir assemblyof claim 9, wherein the plunger comprises a sealing ridge, and theradial energizing spring is configured to engage the sealing ridge insealing contact with the inner surface of the reservoir barrel.
 11. Amethod, comprising: engaging, in a medicament reservoir assembly of aninfusion pump, a static seal with a sealing surface of a rear surface ofa plunger that faces in a direction opposite a dispensing direction whenthe plunger is in a full position; and disengaging the static seal fromthe sealing surface in response to movement in the dispensing directionof the plunger within a reservoir barrel of the medicament reservoirassembly from the full position, wherein a static seal inner diameter ofthe static seal is smaller than an outer diameter of the sealingsurface.
 12. The method of claim 11, wherein the plunger defines anouter surface diameter that is greater than or equal to a static sealouter diameter of the static seal.
 13. The method of claim 11, whereinthe static seal establishes an interference fit with elastomericdeformation with respect to the sealing surface when the plunger is inthe full position.
 14. The method of claim 11, wherein the static sealis a static vapor seal.
 15. The method of claim 11, wherein the staticseal is stationary.
 16. The method of claim 11, wherein the static sealis a face seal.
 17. The method of claim 11, wherein the plunger includesa core integral with a dynamic seal, and the method further comprises:maintaining contact between the dynamic seal and an inner surface of thereservoir barrel as the plunger moves in the dispensing direction. 18.The method of claim 11, further comprising: assisting, by a helperspring, disengagement of the plunger from the static seal.
 19. Themethod of claim 11, wherein the plunger comprises a radial energizingspring configured to radially deform at least a portion of the plunger.20. The method of claim 19, wherein the plunger comprises a sealingridge, and the method further comprises: engaging the sealing ridge insealing contact with the inner surface of the reservoir barrel inresponse to the radial energizing spring radially deforming at least theportion of the plunger.